Temperature-control system



'-LZD. MATTHEWS TEMPERATURE cNTRoL SYSTEM INVENT'OR Filed June 25, 1928 /l/ 9621522204 f, ,O/l/l/ //9/9/ l f 'WITNESSES z fa@ 'ATTORNEY Patented Aug. 28, 1928.

UNITED STATES PATENT OFFICE.

HOWARD D. MATTHEWS, OF MANSIEIELD, OHIO, ASSIGNOR TO` TESTINGHOUSEv ELEC- TRIO & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TEMPERATURE-CONTROL SYSTEM.

Application filed .Tune 23, 1926. Serial No. 117,908.

My invention relatesr to temperature-control systems and particularly to systems tor electrically controlling the heating ot solder or othermaterial in a container.

An object of my invention is toprovide a simple, eliicient, and inexpensive system Ylor controlling the heating ot material.

Another object of my invention is to provide a control system that shall maintain the proper temperature ot' a container independently ot' the quantity ot material in the container.

Another object oi' my invention is to provide a temperaturecontrol system for a solder pot or other container that shall be, at all times, responsive-to the temperature at the surface ot the material therein.

Another object of `my invention is to provide, in a thermostatic-'control system tor material-heating devices, means tor causing athermostat having a normally wide` diilerential to respond to a comparatively small difference in temperature ot'V` the material that is being heated.

Other objects will be obvious from the disclosure.

In the use of electrically heated solder pots and other similar devices, material is withdrawn from time to time and more material added, so'that there will be a varying volume ot material in the pot. The ordinary workman does not dip down to the bottom of the pot when he wishes to take out moltensolder but dips in usually towards the top of the pot.

The material at the bottom and sidesoif the pot will be hotter than at the top, since the top of the solder is exposed to the cooling action ot air. It is, therefore, desirable to provide means to regulatethe heating` ot the solder in accordance with the temperature at its top. Therefore, I provide means for maintaining a temperature-governing device near the top 01"' Vthe solder.

In the manner ot carrying out my invention herein disclosed, 'I provide means for maintaining a thermostatic switch in proxinity to the top surface of the material being heated. This switch governs the operation ot the heating means. Means are also provided to subject the thermostat to the cooling action ot the air outside the material container and to the heating action of an auxiliary heater.

The single figure of the 'accompanying drawing is a cross-sectional view of a solder Y pot with my improved -control system attached thereto.

Referring to the drawing, a solder pot 10 or other container for heating material is composed oiian inner member 12- and an outer member 13, both preferably metallic. rlhe inner and outer members are separated by refractory insulating material 14, that has an yelectric heating` winding 16 embedded therein. The materialto be heated is desi gnated by the reference numeral 18.

The means for energizing the heating.

windingA 1G comprises a conductor 20 that is .secured to one end ot the winding, and a conductor 22 that is attached to an auxiliary heater lmember 26.

The auxiliary heater member 26 has a conductor 27 electrically connected to a terminal member 28 of a' thermostatic switch 29. The thermostat is preferably of the snap acting type disclosed in the patent to il. A. Spencer, No. 1,448,240, granted March 13. 1923.

The other terminal member 30 of the thern'iostatic switch is electrically connected to a conductor 34; The conductor 34 is connected to the winding 1G. The conductors 2O and 22 are electrically connected vto a source ot current (not shown).

Assuming that the. conductor 22 is connected to the positive terminal of the source ot current,v the lpath of current will be Vthrough the conductor 22, the auxiliary heat-l ing member 26, the conductor 27, terminal 28, the thermostatic switch 29, terminal 30,

conductor 34, heating winding 16, and the The thermostatic switch has suitl able registering contact members 31 and 32.

is preferably secured by suitable means, such Y as studs 44, to the container 10. The conduit 38 is preferably open at its top so that the receptacle 36 isin communication with the air outside the container 10.

It will thus be seen that I have provided a means for controlling the heating of the container 10 and, therefore, the temperature of the material 18, that will be responsive to the temperature conditions at the surface of the material 18. Of course, the receptacle 36 and the conduit 38 might be so designed as to maintain the thermostat at some other predetermined position than that shown, either above or below ythe surface Yof the material 18.

Since the Spencer-type thermostat is what may be called a wide-differential thermostat, that is, one in which a relatively large chan'ge of temperature is necessary to cause it to operate, I provide means to cause it to operate on a small change of temperature. Such means, in the present embodiment of my invention, consists of the receptacle 36 and the auxiliary heating member 9.6 which is described and shown as connected in series with the heating coil 1G.

If'we consider the material 18 as being` cool and subject the winding-16 to an electric current for heating the material, this current will also pass'through the auxiliary heating member 2G and thus heat the thermostat more quickly than it would be if it were merely subjected to the heat of the material 18, so that it will act more quickly upon a given increase of temperature of the material than it would if it were subjected only to the heat of the material.

0n the other hand, if the heating winding 16 has been energized for some time, so that the material 18 is at the desired temper- Vature and the thermostatV switch 29 has posed to the air outside of the container.

It will thus be seen that I have provided a means acting upon a relatively small change of temperature for controlling the heating of material, that will be responsive to the temperature conditions existing at or near the surface of the material.

While I have shown and described for pur- 2. In a system for controlling the heating of a liquid container having electric heating means, in combination, supporting means adapted to float on the surface of said liquid, and a thermostatic switch mounted on said supporting means and electrically connected to said electric heating means for controlling the same.

3. In a system for controlling the heating of a varying volume of liquid in a container having electric heating means, in combination, a receptacle adapted to float on the surface of the liquid, guide means for maintaining said receptacle in the proper position, and a thermostatic switch securedinside said receptacle, said switch being electrically connected to the electric heatingmeans for controlling the heating of said liquid. Y

4. In a system for controlling the heating of a varying volumey of material in a pot having electric heating means, in combination, a receptacle adapted to iioat on the surface of the material, a bracket secured to said pot and extending over said material, said bracket having guide members provided with openings therein, a vertical conduit opening at its lower end into said receptacle and slidably mounted in the openings of said guide members, the upper end of said conduit being open, a thermostatic switch positioned in said receptacle and secured thereto, and a pair of conductors extending through said conduit and electrically connected, at their lower ends, to said switch, said conductors being electrically connected at their other ends to said electric heating means.

In testimony whereof, I hereunto subscribe my name this 9 day of June, 1926.

HOWARD n. ini'rrnnws. 

